groups:
  - id: server
    prefix: server
    type: attribute_group
    brief: >
      These attributes may be used to describe the server in a connection-based network interaction
      where there is one side that initiates the connection (the client is the side that initiates the connection).
      This covers all TCP network interactions since TCP is connection-based and one side initiates the
      connection (an exception is made for peer-to-peer communication over TCP where the "user-facing" surface of the
      protocol / API does not expose a clear notion of client and server).
      This also covers UDP network interactions where one side initiates the interaction, e.g. QUIC (HTTP/3) and DNS.
    attributes:
      - id: address
        type: string
        brief: Server address - domain name if available without reverse DNS lookup, otherwise IP address or Unix domain socket name.
        note: |
          When observed from the client side, and when communicating through an intermediary, `server.address` SHOULD represent
          the server address behind any intermediaries (e.g. proxies) if it's available.
        examples: ['example.com']
      - id: port
        type: int
        brief: Server port number
        note: >
          When observed from the client side, and when communicating through an intermediary, `server.port` SHOULD represent
          the server port behind any intermediaries (e.g. proxies) if it's available.
        examples: [80, 8080, 443]
      - id: socket.domain
        type: string
        brief: Immediate server peer's domain name if available without reverse DNS lookup
        examples: ['proxy.example.com']
        note: Typically observed from the client side, and represents a proxy or other intermediary domain name.
        requirement_level:
          recommended: If different than `server.address`.
      - id: socket.address
        type: string
        brief: Server address of the socket connection - IP address or Unix domain socket name.
        note: >
          When observed from the client side, this SHOULD represent the immediate server peer address.

          When observed from the server side, this SHOULD represent the physical server address.
        examples: ['10.5.3.2']
        requirement_level:
          recommended: If different than `server.address`.
      - id: socket.port
        type: int
        brief: Server port number of the socket connection.
        note: >
          When observed from the client side, this SHOULD represent the immediate server peer port.

          When observed from the server side, this SHOULD represent the physical server port.
        examples: [16456]
        requirement_level:
          recommended: If different than `server.port`.